Labor and its abnormalities Flashcards
1
Q
Slow progress in the active phase of labour is described as
A
“primary dysfunctional labour” or protracted
2
Q
cessation of cervical dilatation following a normal portion of active phase dilatation is termed
A
“secondary arrest” of labour.
3
Q
A woman who had protracted labor + “secondary arrest” would described as
A
Combined disorder
4
Q
In Vertex position, what are the AP diameter? It’s measurement ?
A
- Suboccipito-bregmatic (SOB)
9.5 cm
5
Q
In Brow presentation, what is AP diameter? Measurement?
A
Mentovertical(or mentooccipital) the largest transverse diameter, 14 cm > indication for C/S
6
Q
Face presentation,in case of:
Mento anterior & mento posterior what is the diameters? It’s measurements?
A
Mentoanterior: submento bregmatic diameter measuring 9.5 cm
Mentoposterior: submento- vertical measuring 11.5 cm
7
Q
Define Engagement:
A
When the largest transverse diameter In case of vertex (biparietal) has crossed the pelvic brim, the head is stated to be engaged.
Except in platypelloid pelvis where it is supersub parietal diameter
8
Q
The pacemaker of uterine contractions is situated at the……. ?
A
Cornu (the right pacemaker predominates over the left)
9
Q
Adequate uterine contractions features are:
A
3 contractions in 10 mins each lasting for 45 secs and causing Intra-uterine pressure of 65-75 mm of Hg
10
Q
When tachysystole causes Fetal distress it’s called
A
Hyperstimulation < this term abandoned now
11
Q
Abnormal uterine contractions types are:
A
1) hypotonic uterine dysfunction AKA uterine inertia
2) hypertonic uterine dysfunction or Incoordinate uterine dysfunction either the basal tone is elevated appreciably or the pressure gradient is distorted
12
Q
Immediate beneficial effects of ARM: (other than labour augmentation -controversial-):
A
- lowering BP in PET
- relief maternal distress in polyhydro
- control bleeding in APH !
- relief of tension in AP by decreasing intra-uterine pressure and decrease chance of associated coagulopathy
13
Q
In primi’s the most common cause of non engagement at term is
A
Deflexed head, occipitoposterior position followed by CPD
Other causes: Placenta previa, Tumours in the lower segment or Fetal neck, cord around the neck, hydrocephalus, polyhydramnios, distended bladder and rectum.
14
Q
Most common fetal occiput position at engagement
A
LOT > LOA
15
Q
Pain during early stage of labor is due to …. + nerve supply ?
A
Uterine contractions felt along T10- L1
16
Q
Pain during later stages of labor is due to …… + nerve supply ?
A
cervical dilatation felt along s2-s4 (nerve supply of the cervix)
17
Q
Pudendal nerve arises from ….. + site of blockage?
A
From the anterior (ventral) rami of S2,S3,S4, blocked just above the tip of ischial spine (piercing the sacrospinous lig) to block the nerve as it enters the lesser sciatic foramen, 1 cm inferior and medial relative to the attachment of the sacrospinous ligament to the ischial spine.
18
Q
Ferguson reflex:
A
Mechanical stretching of the cervix enhances uterine activity.
Manipulation of the cervix and membrane stripping associated with rise in blood prostaglandin F2a metabolites.
19
Q
The gold standard for cervical ripening is
A
PGE2 dinoprost gel
20
Q
The analogue of prostaglandin which is used in PPH
A
PGF-2
21
Q
The portion of amniotic membrane that covers the head of newborn it’s called ….
A
Caul
22
Q
The percentage of women who deliver on the EDD:
A
4%
23
Q
The portion of amniotic membrane that covers the head of newborn it’s called ….
A
Caul
24
Q
The percentage of women who deliver on the EDD:
A
4%
25
What is the earliest sign of placental separation to appear:
Globular Uterus, firm and ballotable.
26
What is Schroeder’s sign ?
is a placental separation sign where Fundal by slightly raised as the separated placenta comes down in lower segment and uterus rests over it
27
Oxytocin synthesised in:
Paraventricular nucleus of hypothalamus (nonapeptide)
28
Obstetrical shock index (OSI):
HR/systolic BP=
Normal: 0.7-0.8
OSI > 1 indicates massive hge and need for blood transfusion.
29
The 1st step of PPH management:
1- Resuscitate:
- secure IV lines
- volume restoration by NS/RL
- O2
- crossmatching & blood group
+ hemoglobin, clotting time, coagulation profile, electrolytes should be sent as well
30
Living ligature of the uterus is:
Middle layer of myometrium where its fibers running in criss cross manner when contract in labor cause blood vessels constrictions
31
If whole placenta comes out and still USG shows retained placental tissue it is mostly
succenturiate placenta
32
Deep transverse arrest occurs at the level of
Ischial spine
33
Most common malposition is _____, it’s incidence ?
Occipito- posterior position
Mostly (ROP) due to dextro-rotation of the uterus and the presence of the sigmoid colon on the left.
Incidence: At onset of labor - 10%
During late stages : 2%
80-90% cases rotate and become occipito anterior
34
In face presentation the denominator is _________, the commonest position of face presentation is _______. Which pelvic shape common with ? The commonest cause is?
Mentum, Left mento anterior (LMA), common seen in platypelloid pelvic, m/c cause is anencephaly
35
In face presentation the denominator is _________, the commonest position of face presentation is _______. Which pelvic shape common with ? The commonest cause is?
Mentum, Left mento anterior (LMA), common seen in platypelloid pelvic, m/c cause is anencephaly
36
In face presentation the denominator is _________, the commonest position of face presentation is _______. Which pelvic shape common with ? The commonest cause is?
Mentum, Left mento anterior (LMA), common seen in platypelloid pelvic, m/c cause is anencephaly
Other causes: contracted pelvis, prematurity.
37
Overall incidence of complete (flexed) breech among other varieties of breeches is _____, its cord prolapse chances________.
10%, cord prolapse chance is 6%
More in multipara
38
Overall incidence of frank (extended legs) breech among other varieties of breeches is _____, its cord prolapse chances________.
70%, 0.5% ,
more in PG due to tight abdominal wall-
39
In footling breech among other varieties of breeches the cord prolapse chances is ________.
12%
C/S has to be done
40
Stargazer breech ✨
Breech+ extended fetal head > indication for C/S
41
ECV prerequisites:
1) GA> 37 wks
2) adequate liquor
3) intact membrane
4) no vaginal delivery contraindications
5) facility of emergency C/S
42
Absolute Contraindications of ECV:
-PP
- multifetal pregnancy
- vaginal delivery contraindications
- hx of Antepartum hge
- IUGR
- severe preeclampsia & HTN
- ROM
- known uterine malformation
43
Relative Contraindications of ECV:
- early labor
- oligohydramnios
- ROM
- k/c of nuchal cord
- structural uterine abnormalities
- fetal growth restriction
- prior assumption on its risks
- previeus C/S
44
Emergency C/S chance with ECV:
0.5%
45
Breech Vaginal delivery can be done only if Zatuchni-Andros score is more than ?
4 , if less C/S indicated
46
Breech, denominator ? Most common position?
Sacrum, left sacroanterior
47
Engaging diameter in breech is:
Bitrochanteric (10 cm)
Always give episiotomy in breech
48
If buttocks not delivered spontaneously in breech what mameuver can be done:
1) Groin traction
2) pinard maneuver
49
To prevent cord from shrivelling in breech assisted delivery wrap the baby in warm towel after delivery of the body and before delivery of head, this called ....... technique.
Savage
50
If Shoulders delivery in breech doesn’t deliver spontaneously, it can vibe delivered by ....... manoeuvre
Lovset
51
The Engagement diameter of shoulders is______, measuring ?
bisacromial diameter (12 cm)
52
The engagement diameter of head in breech is________
Suboccipitofrontal (10cm),
53
Unstable lie causes:
• Grand multipara (commonest)
• polyhydramnios
• contracted pelvis
• placenta previa
• pelvic tumor
54
Most common cause of fetal death in unstable lie is
Cord prolapse
55
Maximum chances of cord prolapse are with: (by order)
Transverse lie>footling>knee> complete breech> frank breech
56
Deep transverse arrest can be Managed by:
• Caesarean section
• vacuum delivery
• Kielland forceps
• manual rotation
57
Dead baby in Transverse lie with shoulder presentation is called as
Neglected shoulder presentation
58
The most frequent single cause of death in breech presentation is
Intracranial hge due to tentorial tears
59
In direct Occipito-posterior position (face to pubic delivery) most commonly encountered problem is:
Complete perineal tears due to the longer biparietal diameter (9.4cm) distended the perineum rather than the smaller bitemporal diameter (8cm), episiotomy should be given
60
Vaginal delivery is not possible in:
• brow presentation
• shoulder presentation (transverse lie)
• mentoposterior presentation of face (i.e. when chin lies directed to sacrum)
61
Incidence of breech
at 28 wks: 20-25%
At 32 wks: 7% or 5-15%
at term: 2-3% or 3.5%
62
Causes of breech presentation at term:
factors that prevent spontaneous version:
• breech with extended legs
• twins
• oligohydramnious
• congenital malformation of uterus like separate and bicornuate
• short cord
• IUD of fetus
Favourable adaptation: hydrocephalus, PP, corneal fundal placenta, contracted pelvis,
, multipara with lax abdomen
63
Best time for episiotomy in breech:
Climbing of perineum
64
Most common cause of OP position
Android pelvis/ Deflexed head
65
tokophobia
fear of childbirth and contractions
66
Most common congenital anomaly associated with face presentation
Anencephaly
67
Most common pelvis associated with face presentation
Platypelloid pelvis
68
ECV success rate is
50-80 %
69
Symphysiotomy
is a surgical procedure in which the cartilage of the pubic symphysis is divided to widen the pelvis allowing childbirth of breech with after coming head entrapement not responding to other manoeuvres
Other: zeffenelli manoeuvre
70
Internal podalic version, when it is used ?
Only used for the 2nd twin when it’s lying transversely and external version fails.
71
Prerequisites for IPV:
-Intact membrane or recently ruptured
- Cx fully dilated
- fetus must be living
72
Complications of internal podalic version:
1- maternal: Placenta abruption, rupture uterus, increase morbidity
2- Fetal: asphyxia, cord prolapse, ICH
73
Per-Abdomen Clinical features of obstructed labor:
stretched lower uterine segment, contracted upper uterine segment, Bandl’s ring (retraction ring), fetal distress or absent FH
74
Per-vaginal Clinical features of obstructed labor:
-Dry, hot vagina
Offensive purulent vaginal discharge
Caput/Moulding
Urethral compression and distended bladder
Bladder injury and hematuria .
75
Risk of uterine rupture With induction or augmentation vs. Spontaneous VBAC
the two- to three-fold increased risk of uterine rupture and around 1.5-fold increased risk of caesarean delivery in induced and/or augmented labour compared with spontaneous VBAC labour.
76
IOL and amniotomy
induction of labour using mechanical methods (amniotomy or Foley catheter) is associated with a lower risk of scar rupture compared with induction using prostaglandins.
77
Bandl’s ring
Retraction ring
78
Schroeder’s ring
Constriction ring
( can be palpated per vaginally not abdomen)
79
The most common cause of fetal loss in breech is
ICH due to tear of tentorium cerebelli and flax cerebri
80
Vacuum indications same as forceps except that
In fetal distress vacuum is not used ??
81
More common complications with Vacuum:
- cephalohematoma
- subgaleal hematoma
- retinal nerve injury
- sixth nerve palsy
82
Labor and amniotimy
Amniotomy in the first stage of labor results in shorter labor, but it also may be associated with variable fetal heart rate decelerations; therefore, it should be reserved for slowly progressing labors.
83
the manoeuvres done for delivery of after coming head are:
• burns- Marshall technique.
• kristeller maneuver
• Bracht maneuver
• malar flexion and shoulder traction (mauriceau-smellie-veit technique)
• Wigand-Martin technique
• Naville-Barnes forceps
• pipers forceps And Prague maneuver for Occipitoposterior delivery in breech.
If head stuck due to incomplete Cx dilatation you can do Duhrssen incision at 2, 10 and 6 o'clock to avoid uterine arteries. If
84
Phases of parturition:
1) a prelude to it
2) the preparation for it
3) the process itself
4) recovery
85
Phases of active phase of 1st stage of labor:
1) Acceleration phase
2) phase of Maximum slope
3) deceleration phase
86
Factors that regulate phase 1 of parturition:
That act on uterus:
- prostacyclin
- Nitric oxide
- hCG
- CRH
- caspase 3
That act on uterus and cervix:
- progesterone
- PGDH
87
Factors that regulate phase 2 of parturition:
That act on uterus:
- uterine stretch
- Gap junction receptors
- fetal signals (SPA, PAF, CRH)
- Fetal membrane senescence
- prostaglandins
- cortisol ?
That act on cervix:
Hyaluronan
That acts on both:
- Progesterone (non-classic withdrawal)
- Estrogen
- Relaxin
88
Factors that regulate phase 3 of parturition:
That act on uterus:
- Prostaglandins
- oxytocin
- CRH?
- inflammatory cell activation
That act on both cervix and uterus:
- estrogen
- Relaxin
89
Factors that regulate phase 4 of parturition:
That act on uterus:
- oxytocin
That act on both uterus and cervix:
- inflammatory cell activation
90
1st phase of labor: uterine Quiescence achieved by:
1) diminished Intracellular crosstalk and reduced IC Ca levels
2) ion-channel regulation of cell membrane potential
3) activation of uterine endoplasmic reticulum stress-unfolded protein response
4) uterotonin degradation
91
Phase 2 of Labor uterine activation happened due to:
1) progesterone withdrawal by progesterone receptors inactivation
2) myometrial changes by contraction associated protein expression and formation of lower uterine segment from the isthmus led to fetal descending (called lightening)
3) oxytocin receptors rise
92
Resting tone of uterus in labor:
10-25 mmHg
93
The percentage that breech will correct position upon 30 wks
13%
94
The percentage that breech will correct position at term
30%
95
Absolute Contraindications of VBAC
Planned VBAC is contraindicated in women with previous uterine rupture or classical caesarean scar and in women who have other absolute contraindications to vaginal birth that apply irrespective of the presence or absence of a scar (e.g. major placenta praevia).
96
Can women with two or more prior caesareans be offered planned VBAC?
Women who have had two or more prior LSCS deliveries may be offered VBAC after counselling by a senior obstetrician. This should include the risk of uterine rupture and maternal morbidity, and the individual likelihood of successful VBAC (e.g. given a history of prior vaginal delivery). Labour should be conducted in a centre with suitable expertise and resources to immediate surgical delivery. [New 2015 RCOG]
97
risk of uterine rupture in women undergoing VBAC?
planned VBAC is associated with an approximately 1 in 200 (0.5%) risk of uterine rupture.
98
What is the likelihood of VBAC success?
the success rate of planned VBAC is 72–75%.
99
trial of vaginal delivery after two Caesarean sections, success rate? Risk of uterine rupture?
success rate 71.1%, uterine rupture rate 1.36% and of a comparative maternal morbidity with repeat CS option.
100
Sulcus tears
vaginal tears occurring in the upper half to third of the vagina in the absence of a third or fourth degree tear. It is important to avoid these tears, because they are deep, often penetrate perirectal fatty tissue, bleed profusely and are difficult to repair.
101
Active management of the 3rd stage of labour reduce the incidence of PPH by up to —%.
reduce the incidence of PPH by up to 66%.
102
Contraindications to Elective Vaginal Breech Delivery
Macrosomia
Lack of physician experience with vaginal breech delivery
Footling breech presentation
Unfavorable pelvis
Occult cord prolapse
Intrauterine growth restriction
Lack of facilities and personnel to switch rapidly to cesarean delivery
Fetal anomalies preventing vaginal delivery Clinical or x-ray evidence of inadequate pelvis Extended (stargazing) head on ultrasound
examination
103
regard to an OP position common associated features:
90% rotate to OA. All OP positions are deflexed to a degree.
With A persistent anterior lip is common.
Back pain is a common feature of early labour.
104
Cord compression causes the pH to fall by — per minute
Cord compression causes the pH to fall by 0.04 per minute
105
labor abnormalities are best described as
1- protraction disorders (ie, slower than normal progress)
106
Stages and phases of labor
First stage = Time from onset of labor to complete cervical dilation
consists of a latent phase and an active phase.
107
cervical dilation in normal labor can be slower than 1 cm per hour and still have a high chance of vaginal delivery with normal perinatal outcomes, and the cervix does not dilate linearly (it is a hyperbolic pattern)
Contemporary data suggest that the normal rate of cervical change between 3 and 6 cm dilation is much slower than described by Friedman, who reported minimum dilation should be at least 1 cm/hour. Many contemporary women who go on to deliver vaginally have rates of cervical dilation <1 cm/hour before reaching 6 cm dilation. Indeed, both nulliparas and multiparas who go on to deliver vaginally can take more than six hours to dilate from 4 cm to 5 cm and more than three hours to dilate from 5 cm to 6 cm
108
The 2014 Obstetric Care Consensus statement of recommendations for safe prevention of primary cesarean delivery by the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine stated that before diagnosing arrest in the second stage of labor, clinicians should
allow nulliparous women to push for at least three hours and multiparous women to push for at least two hours, and commented that longer durations might be appropriate for women with epidural anesthesia
109
Recurrence rate of shoulder dystocia
10 fold
110
cesarean delivery may be offered to a woman with a history of OASIS if: (ACOG Guidelines)
she experienced anal incontinence after a previous delivery, she had complications including wound infections or need for repeat repair, or if she reports experiencing psychological trauma as a result of the previous OASIS and requests a cesarean delivery.
111
Risk of OASIS:
-use of forceps (up to 13-fold)
- vacuum-assisted deliveries (up to 4-fold)
-Increasing duration of the second stage
- midline episiotomies
- vertex malpresentation (primarily occiput posterior)
112
Antibiotics given in OASIS:
The only randomized-controlled trial of antibiotics in OASIS repair used a second-generation cephalosporin (1 gram of cefoxitin or cefotetan) or, in allergic patients, 900 mg of clindamycin This reduced rates of postoperative wound complications from 24% to 8% (p=0.04)
113
Face presentation incidence
1 In 500
114
Brow presentation incidence
1 in 1000
115
Uterine smooth muscles contractions are painful hypothesis:
1) hypoxia of contracted myometrium.
2) compression of nerve ganglia in the cervix and lower uterus by contracted interlocking muscle bundles.
3)cervical stretching during dilation.
4) stretching of the peritoneum overlying the fundus.
116
Leopold maneuvers sensitivity and specificity, PPV, NPV
Sensitivity 88%
Specificity 94%
PPV 74%
NPV 97%
117
Risk factors of urine retention post delivery:
1) primiparity
2) oxytocin-induced or augmented labor
3) perineal lacerations
4) operative vaginal delivery
5) catheterization during labor
6) labor induction >10 hrs
118
The median duration of 2nd stage for nullipara and multipara
50 min for nullipara and about 20 min for multipara
119
Maternal monitoring intrapartum of Temperature, Blood pressure, pulse are evaluated every
4 hrs
120
Labor disorders
- latent-phase prolongation
- Active phase disorders
* protraction disorder
* arrest disorder
121
Precipitous labours linked to …. And associated with (Maternal and fetal side effects)
If cervix not effaced with non-compliant birth canal May lead to uterine rupture or extensive lacerations in that circumstance Amniotic fluid most likely develops.
Also associated with placental abruption, meconium, postpartum hge, low apgar score.
Or newborn injuries.
122
Inlet contraction usually is defined as a diagonal conjugate
< 11.5 cm
123
In women with contracted pelves, face and shoulder presentation are encountered — times more, and cord prolapses —- to — times.
In women with contracted pelves, face and shoulder presentation are encountered three times more, and cord prolapses four to six times.
124
Contracted midpelvis is more common than Inlet contraction and frequently causes ….
Transverse arrest of fetal head
125
Contracted midpelvis is most likely when the sum of the interspinous and posterior sagittal diameters of the midpelvis is .. cm
What is the normal limit ?
Normally is 15.5 cm (10.5+5)
Abnormal if fall to 13.5 cm or less.
126
Contracted outlet defined as
An interischial tuberous diameter of 8 cm or less.
127
Chance of VBAC after TOLAC
60-80%
74% in summary Meta analysis from AHRQ
128
Clinical factors associated with successful TOLAC
Increased probability of success
• prior vaginal birth
• spontaneous Labor
Decreased probability of success
• recurrent indication for initial CD (Labor dystocia)
• increased maternal age
• non-white ethnicity
• Gestational age > 40 wks
• maternal obesity
• preeclampsia
• short inter pregnancy interval
• increased neonatal birth weight
129
Causes of face presentation
- Preterm fetuses
- neck enlargement
- cord coils around the neck
- fetal malformation (anencephaly)
- hydramnious
- high parity
130
Common causes of transverse lie
1) abd wall relaxation from high parity (>4 deliveries ten folds risk)
2) preterm fetuses
3) placenta previa
4) abnormal uterine anatomy
5) hydramnios
6) contracted pelvis
131
first stage of labor defined as
Completed latent phase + contractions> 200 montevideo units for >2 hrs without cervical change
132
The incidence of uterine rupture in TOLAC in previous 1xCS is
< 1%.
(0.5 % [1:200])
133
- Bracht's manoeuvre
After the arms are delivered, the infant is grasped by the hips and lifted with two hands toward the mother's stomach, without any traction, the neck pivoting around the symphysis.
• Having an assistant apply suprapubic pressure facilitates delivery of the aftercoming head.
134
There are 2 ways of placental Separation (physioIogically)
- Duncan mechanism: Blood escape to vagina first then Placenta follow.
- Schultze mechanism: Blood remained Concealed Behind placenta till it Delivered
135
Maternal complications with labor induction are
CS (2-3X) ?, chorioamnionitis, uterine rupture, postpartum hge from uterine stony.
136
the incidence of brachial nerve injury --- per 1000 vaginal deliveries and --- per 1000 cesarean deliveries?
1.5 % / 0.17 %
137
The C5–6 roots join to form the upper trunk of the
plexus, and injury leads to paralysis of which muscles ?
the deltoid, infraspinatus, and flexor muscles of the forearm. The affected arm is held straight and internally rotated, the elbow is extended, and the wrist and fingers flexed. Finger function usually is retained. Because lateral traction on the fetal head is frequently employed to effect delivery of the shoulders in normal vertex presentations, most cases of Erb paralysis follow deliveries that do not appear difficult.
138
There are only a few conditions in which the fetal body does not deliver promptly following the head, DDx
-shoulder dystocia
- short umbilical cord
- fetal thoracic / Abdominal enlargement
- Locked / conjoined twins
- contracted ring
139
Defined as the Shortest diameter between Sacrum and symphysis pubis
obstetric conjugate
140
Most common cause of breech presentation:
Prematurity
141
The greatest diameter of the fetal head is:
Verticomental (13.5 cm)
- brow presentation-
142
The transport of prostaglandins from the amnion to maternal tissues is limited by expression of the inactivating enzyme which is called ...... and excreted from -----
prostaglandin dehydrogenase (PGDH), in the chorion. During labor, PGDH levels decline, and amnion-derived prostaglandins can influence membrane rupture and uterine contractility.
143
The chorion is a primarily protective tissue layer and provides immunological acceptance. It is also enriched with enzymes that inactivate uterotonins, which are agents that stimulate contractions. Inactivating enzymes include
prostaglandin dehydrogenase, oxytocinase, and enkephalinase
144
Prostaglandins are produced using plasma membrane derived ------------ which usually is released by the action of ----------. The enzymes type 1 and 2 prostaglandin H synthase (PGHS-1 and -2), also known as ----- , convert ------ --- to ------- --- (PGH2). These enzymes are the target of many nonsteroidal antiinflammatory drugs (NSAIDs).
Prostaglandins are produced using plasma membranederived arachidonic acid, which usually is released by the action of phospholipase A2 or C. The enzymes type 1 and 2 prostaglandin H synthase (PGHS-1 and -2), also known as cyclooxygenase 1 and 2 (COX-1 and -2), convert arachidonic acid to prostaglandin H2 (PGH2). These enzymes are the target of many nonsteroidal antiinflammatory drugs (NSAIDs).
145
The quiescence of phase 1 likely stems from:
(1) actions of estrogen and progesterone via intracellular receptors, (2) myometrial-cell plasma membrane receptor–mediated increases in cyclic adenosine monophosphate (cAMP), (3) generation of cyclic guanosine monophosphate, and (4) other systems, including modification of myometrial-cell ion channels.
146
employing x-ray pelvimetry, demonstrated that the incidence of difficult deliveries rises when either the anteroposterior diameter of the inlet is <—cm or the transverse diameter is <—cm. Either threshold can be used to consider a pelvis contracted. As expected, when both diameters are shortened, dystocia rates are much greater than when only one is diminished.
employing x-ray pelvimetry, demonstrated that the incidence of difficult deliveries rises when either the anteroposterior diameter of the inlet is <10 cm or the transverse diameter is <12 cm. Either threshold can be used to consider a pelvis contracted. As expected, when both diameters are shortened, dystocia rates are much greater than when only one is diminished.
147
the midpelvis is likely contracted when the sum of the interspinous and posterior sagittal diameters of the midpelvis—normally, — plus — cm, or —- cm falls to — cm or less. Or Midpelvic contraction is suspected whenever the interspinous diameter is <— cm. When it measures <—cm, the midpelvis is contracted.
, the midpelvis is likely contracted when the sum of the interspinous and posterior sagittal diameters of the midpelvis—normally, 10.5 plus 5 cm, or 15.5 cm—falls to 13.5 cm or less. Midpelvic contraction is suspected whenever the interspinous diameter is <10 cm. When it measures <8 cm, the midpelvis is contracted.
148
The flexion point of vacuum application is found along
the sagittal suture, approximately 3 cm from the posterior fontanel’s center and approximately 6 cm from the anterior fontanel’s center. Because most cup diameters measure 5 to 6 cm, when properly placed, the cup rim lies at the posterior fontanel’s border and 3 cm from the anterior fontanel
149
maternal indications of operative vaginal delivery
the most common are maternal exhaustion and prolonged second-stage labor.
preexisting or intrapartum conditions that limit effective pushing or warrant expedited delivery. Severe or acute pulmonary compromise, decompensation from intrapartum infection, neurological disease, and serious cardiac disorders are examples. Frequent fetal indications include nonreassuring fetal heart rate and premature placental separation
150
the cause of a persistent OP position and of the difficulty in accomplishing rotation is
an anthropoid pelvis. This architecture opposes rotation and predisposes to posterior delivery
151
Women with a nonrecurring indication—for example, breech presentation— have the highest successful TOLAC rate—nearly .. percent (Wing, 1999). Those with a prior cesarean delivery for fetal compromise have an approximately ..-percent VBAC rate, and for those done for labor arrest, VBAC rates approximate only .. percent.
Women with a nonrecurring indication—for example, breech presentation— have the highest successful TOLAC rate—nearly 90 percent (Wing, 1999). Those with a prior cesarean delivery for fetal compromise have an approximately 80-percent VBAC rate, and for those done for labor arrest, VBAC rates approximate only 60 percent.
152
Which of the following pelvic types is generally
associated with persistent occiput posterior position?
Anthropoid
153
Considering breech diagnosed at 36 weeks GA, what is the chance that a noncephalic presentation will persist at delivery?
- 80%
154
What were the main outcomes in the term breech trial?
- lower perinatal and neonatal mortality - 3/1039 in C/S group
- 13/ 1039 in vaginal group - lower neonatal serious morbidity
- 14/1036 in C/S group
- 39/1026 in vaginal group
* this group includes birth trauma, seizures, hyptonia, abnormal LOC, low apgar scores, base deficit >15, pH <7.00, intubation/ventilation, tube feeding, care in NICU
- no difference in maternal serious morbidity or mortality - 3.6% had serious morbidity
* this includes postpartum bleeding, genital tract injury, wound infection/breakdown, systemic infection
155
What are the factors that reduce the success rate of an ECV:
- nulliparity (most consistent factor associated with failure)
- oligohydramnios (2nd most important factor is amniotic fluid) - engaged/descended breech
- anterior placenta
- ant/post position of fetal spine
- tense uterus, difficulty palpating fetal head
- obesity
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There is entrapment of the aftercoming head? What are the next steps?
- Make episiotomy (or enlarge existing one if needed)
- Piper or (Laufe forceps)
- IV nitro (utrerine relaxation)
- the Bracht maneuver can be attempted
- Duhrssen cervical incisions (if cervix not fully- dilated)
- Zavenelli maneuver - abdominal rescue
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When microcephalic can be delivered vaginally ?
with milder forms of hydrocephaly, if the biparietal diameter is <10 cm or if the head circumference is <36 cm, vaginal delivery may be permitted
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When macrocephalic can be delivered vaginally ?
with milder forms of hydrocephaly, if the biparietal diameter is <10 cm or if the head circumference is <36 cm, vaginal delivery may be permitted
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